Data

K-Axis dissolved iron (dFe) data from the Kerguelen-Axis region of the Southern Ocean

Australian Antarctic Division

Schallenberg, C. and Bowie, A. ; SCHALLENBERG, CHRISTINA ; BOWIE, ANDREW ROSS

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ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rfr_id=info%3Asid%2FANDS&rft_id=info:doi10.4225/15/5a77d6bd5975e&rft.title=K-Axis dissolved iron (dFe) data from the Kerguelen-Axis region of the Southern Ocean&rft.identifier=10.4225/15/5a77d6bd5975e&rft.publisher=Australian Antarctic Data Centre&rft.description=These data were collected on the K-Axis voyage of the Aurora Australis, in 2016. The voyage was so named because data were collected along the Kerguelen Axis of the undersea Kerguelen Plateau.Sampling was conducted according to GEOTRACES protocols. Samples for trace element analyses, including dissolved iron (dFe), were filtered through acid-cleaned 0.2 um cartridge filters (Pall Acropak) under constant airflow from several ISO class 5 HEPA units. All plastic ware was acid-cleaned prior to use, following GEOTRACES protocols. Samples were collected into low-density polyethylene (LDPE) bottles, acidified immediately to pH 1.7 with Seastar Baseline hydrochloric acid (HCl), double-bagged and stored at room temperature until analysis on shore. Samples for dFe analysis were pre-concentrated offline (factor 40) on a SeaFAST S2 pico (ESI, Elemental Scientific, USA) flow injection system with a Nobias Chelate-PA1 column. Samples were eluted from the column in 10% distilled nitric acid (HNO3), with calibration based on the method of standard additions in seawater (made using multi-element standards in a 10% HNO3 matrix, rather than an HCl matrix). Pre-concentrated samples were analysed using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Inc.). Data were blank-corrected by subtracting an average acidified milli-Q blank that was treated similarly to the samples. The dFe detection limit for a given analysis run on the SeaFAST/SF-ICP-MS was calculated as 3 x standard deviation of the milli-Q blank on that run. Detection limits ranged from 0.016 to 0.067 nmol kg-1, with a median of 0.026 nmol kg-1 (n=12). GEOTRACES reference materials were analysed along with samples and results were in good agreement with consensus values: SAFe D1 was measured at 0.69 +/- 0.05 nmol kg-1 (n=7; consensus value = 0.67 +/- 0.04 nmol kg-1) and GD was measured at 1.02 +/- 0.01 nmol kg-1 (n=6; consensus value = 1.00 +/- 0.1 nmol kg-1). Comments regarding the data spreadsheet:NaN = no sampledFe QC flags: 1 = high confidence in data quality 2 = detection limit 3 = low confidence in data qualitydetection limits: dFe data that were below the daily detection limit were replaced with the respective detection limit. They are flagged with the number 2 in the dFe QC flag column.Progress Code: completedStatement: No problems with analysis, but there were a lot of problems with GO-FLO bottles during sampling, i.e. bottles either not closing or leaking on arrival on deck. As a result, there is a large number of missing samples (NaN), and we also took some salinity samples for additional data quality control as follows: A subset of salinity samples (n=124) was taken from GO-FLO bottles to check whether bottles had closed at the expected depths and/or whether there were problems with leaking. Salinity samples were compared to CTD salinities, and samples where measured salinity did not match the respective CTD salinity (n=9) were flagged as suspect and are not included in the data sheet. Note that salinity checks were predominantly performed on GO-FLO bottles that were suspicious (e.g. leaking), so they do not represent a random set of samples.&rft.creator=Schallenberg, C. and Bowie, A. &rft.creator=SCHALLENBERG, CHRISTINA &rft.creator=BOWIE, ANDREW ROSS &rft.date=2018&rft.coverage=westlimit=70; southlimit=-66; eastlimit=95; northlimit=-57&rft.coverage=westlimit=70; southlimit=-66; eastlimit=95; northlimit=-57&rft_rights=These data are publicly available for download from the provided URL.&rft_rights=Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/legalcode&rft_rights=This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4344_dFe when using these data.&rft_rights=This metadata record is publicly available.&rft_subject=oceans&rft_subject=EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > NUTRIENTS&rft_subject=EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > TRACE ELEMENTS&rft_subject=EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > DISSOLVED SOLIDS&rft_subject=IRON&rft_subject=DISSOLVED IRON&rft_subject=K-AXIS&rft_subject=KERGUELEN AXIS&rft_subject=4344&rft_subject=AAS 4344&rft_subject=GO-FLO BOTTLES&rft_subject=SHIPS&rft_subject=R/V AA > R/V Aurora Australis&rft_subject=R/V UM > R/V UMITAKA MARU&rft_subject=AMD/AU&rft_subject=ACE/CRC&rft_subject=CEOS&rft_subject=AMD&rft_subject=GEOGRAPHIC REGION > POLAR&rft_subject=CONTINENT > ANTARCTICA&rft_subject=OCEAN > SOUTHERN OCEAN > Banzare Bank&rft_subject=OCEAN > INDIAN OCEAN > KERGUELEN ISLANDS&rft.type=dataset&rft.language=English Access the data

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Attribution 4.0 International (CC BY 4.0)
https://creativecommons.org/licenses/by/4.0/legalcode

These data are publicly available for download from the provided URL.

This data set conforms to the CCBY Attribution License (http://creativecommons.org/licenses/by/4.0/). Please follow instructions listed in the citation reference provided at http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4344_dFe when using these data.

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Full description

These data were collected on the K-Axis voyage of the Aurora Australis, in 2016. The voyage was so named because data were collected along the "Kerguelen Axis" of the undersea Kerguelen Plateau.

Sampling was conducted according to GEOTRACES protocols. Samples for trace element analyses, including dissolved iron (dFe), were filtered through acid-cleaned 0.2 um cartridge filters (Pall Acropak) under constant airflow from several ISO class 5 HEPA units. All plastic ware was acid-cleaned prior to use, following GEOTRACES protocols. Samples were collected into low-density polyethylene (LDPE) bottles, acidified immediately to pH 1.7 with Seastar Baseline hydrochloric acid (HCl), double-bagged and stored at room temperature until analysis on shore.

Samples for dFe analysis were pre-concentrated offline (factor 40) on a SeaFAST S2 pico (ESI, Elemental Scientific, USA) flow injection system with a Nobias Chelate-PA1 column. Samples were eluted from the column in 10% distilled nitric acid (HNO3), with calibration based on the method of standard additions in seawater (made using multi-element standards in a 10% HNO3 matrix, rather than an HCl matrix). Pre-concentrated samples were analysed using Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS, Thermo Fisher Scientific, Inc.). Data were blank-corrected by subtracting an average acidified milli-Q blank that was treated similarly to the samples.

The dFe detection limit for a given analysis run on the SeaFAST/SF-ICP-MS was calculated as 3 x standard deviation of the milli-Q blank on that run. Detection limits ranged from 0.016 to 0.067 nmol kg-1, with a median of 0.026 nmol kg-1 (n=12). GEOTRACES reference materials were analysed along with samples and results were in good agreement with consensus values: SAFe D1 was measured at 0.69 +/- 0.05 nmol kg-1 (n=7; consensus value = 0.67 +/- 0.04 nmol kg-1) and GD was measured at 1.02 +/- 0.01 nmol kg-1 (n=6; consensus value = 1.00 +/- 0.1 nmol kg-1).

Comments regarding the data spreadsheet:
NaN = no sample
dFe QC flags:
1 = high confidence in data quality
2 = detection limit
3 = low confidence in data quality
detection limits: dFe data that were below the daily detection limit were replaced with the respective detection limit. They are flagged with the number 2 in the dFe QC flag column.

Lineage

Progress Code: completed

Statement: No problems with analysis, but there were a lot of problems with GO-FLO bottles during sampling, i.e. bottles either not closing or leaking on arrival on deck. As a result, there is a large number of missing samples (NaN), and we also took some salinity samples for additional data quality control as follows: A subset of salinity samples (n=124) was taken from GO-FLO bottles to check whether bottles had closed at the expected depths and/or whether there were problems with leaking. Salinity samples were compared to CTD salinities, and samples where measured salinity did not match the respective CTD salinity (n=9) were flagged as suspect and are not included in the data sheet. Note that salinity checks were predominantly performed on GO-FLO bottles that were suspicious (e.g. leaking), so they do not represent a random set of samples.

Notes

Purpose
Supply dissolved iron data for the K-axis region. Complimentary to other K-axis data.

Data time period: 2017-01-10 to 2018-02-28

This dataset is part of a larger collection

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text: westlimit=70; southlimit=-66; eastlimit=95; northlimit=-57

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Other Information

Download the data (GET DATA > DIRECT DOWNLOAD)

url : https://data.aad.gov.au/eds/4595/download External Link

Public information for AAS project AAS_4344 (PROJECT HOME PAGE)

url : https://projects.aad.gov.au/report_project_public.cfm?project_no=AAS_4344 External Link

Citation reference for this metadata record and dataset. (VIEW RELATED INFORMATION)

url : https://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=AAS_4344_dFe External Link

Identifiers

DOI : 10.4225/15/5A77D6BD5975E
global : AAS_4344_dFe